A millimeter-wave multifunction sensor for wireless monitoring of displacement and velocity

A novel multi-function millimeter-wave integrated-circuit sensor operating at 35.6 GHz has been developed and demonstrated for monitoring of displacement and low velocity. Measured displacement results show an unprecedented resolution of only 10 μm, approximately equivalent to λ₀/840 in terms of free-space wavelength λ₀, with a maximum error of only 27 μm. The sensor can measure speed as low as 27.7 mm/s, corresponding to 6.6 Hz in Doppler frequency, with an estimated velocity resolution of 2.7 mm/s.